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linux-next/fs/jbd/recovery.c
Jose R. Santos 9ad163ae0d JBD: Fix JBD warnings when compiling with CONFIG_JBD_DEBUG
Note from Mingming's JBD2 fix:

Noticed all warnings are occurs when the debug level is 0.  Then found the
"jbd2: Move jbd2-debug file to debugfs" patch
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=0f49d5d019afa4e94253bfc92f0daca3badb990b

changed the jbd2_journal_enable_debug from int type to u8, makes the
jbd_debug comparision is always true when the debugging level is 0.  Thus
the compile warning occurs.

Thought about changing the jbd2_journal_enable_debug data type back to int,
but can't, because the jbd2-debug is moved to debug fs, where calling
debugfs_create_u8() to create the debugfs entry needs the value to be u8
type.

Even if we changed the data type back to int, the code is still buggy,
kernel should not print jbd2 debug message if the jbd2_journal_enable_debug
is set to 0.  But this is not the case.

The fix is change the level of debugging to 1.  The same should fixed in
ext3/JBD, but currently ext3 jbd-debug via /proc fs is broken, so we
probably should fix it all together.

Signed-off-by: Jose R. Santos <jrs@us.ibm.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:35 -07:00

593 lines
14 KiB
C

/*
* linux/fs/jbd/recovery.c
*
* Written by Stephen C. Tweedie <sct@redhat.com>, 1999
*
* Copyright 1999-2000 Red Hat Software --- All Rights Reserved
*
* This file is part of the Linux kernel and is made available under
* the terms of the GNU General Public License, version 2, or at your
* option, any later version, incorporated herein by reference.
*
* Journal recovery routines for the generic filesystem journaling code;
* part of the ext2fs journaling system.
*/
#ifndef __KERNEL__
#include "jfs_user.h"
#else
#include <linux/time.h>
#include <linux/fs.h>
#include <linux/jbd.h>
#include <linux/errno.h>
#include <linux/slab.h>
#endif
/*
* Maintain information about the progress of the recovery job, so that
* the different passes can carry information between them.
*/
struct recovery_info
{
tid_t start_transaction;
tid_t end_transaction;
int nr_replays;
int nr_revokes;
int nr_revoke_hits;
};
enum passtype {PASS_SCAN, PASS_REVOKE, PASS_REPLAY};
static int do_one_pass(journal_t *journal,
struct recovery_info *info, enum passtype pass);
static int scan_revoke_records(journal_t *, struct buffer_head *,
tid_t, struct recovery_info *);
#ifdef __KERNEL__
/* Release readahead buffers after use */
static void journal_brelse_array(struct buffer_head *b[], int n)
{
while (--n >= 0)
brelse (b[n]);
}
/*
* When reading from the journal, we are going through the block device
* layer directly and so there is no readahead being done for us. We
* need to implement any readahead ourselves if we want it to happen at
* all. Recovery is basically one long sequential read, so make sure we
* do the IO in reasonably large chunks.
*
* This is not so critical that we need to be enormously clever about
* the readahead size, though. 128K is a purely arbitrary, good-enough
* fixed value.
*/
#define MAXBUF 8
static int do_readahead(journal_t *journal, unsigned int start)
{
int err;
unsigned int max, nbufs, next;
unsigned long blocknr;
struct buffer_head *bh;
struct buffer_head * bufs[MAXBUF];
/* Do up to 128K of readahead */
max = start + (128 * 1024 / journal->j_blocksize);
if (max > journal->j_maxlen)
max = journal->j_maxlen;
/* Do the readahead itself. We'll submit MAXBUF buffer_heads at
* a time to the block device IO layer. */
nbufs = 0;
for (next = start; next < max; next++) {
err = journal_bmap(journal, next, &blocknr);
if (err) {
printk (KERN_ERR "JBD: bad block at offset %u\n",
next);
goto failed;
}
bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
if (!bh) {
err = -ENOMEM;
goto failed;
}
if (!buffer_uptodate(bh) && !buffer_locked(bh)) {
bufs[nbufs++] = bh;
if (nbufs == MAXBUF) {
ll_rw_block(READ, nbufs, bufs);
journal_brelse_array(bufs, nbufs);
nbufs = 0;
}
} else
brelse(bh);
}
if (nbufs)
ll_rw_block(READ, nbufs, bufs);
err = 0;
failed:
if (nbufs)
journal_brelse_array(bufs, nbufs);
return err;
}
#endif /* __KERNEL__ */
/*
* Read a block from the journal
*/
static int jread(struct buffer_head **bhp, journal_t *journal,
unsigned int offset)
{
int err;
unsigned long blocknr;
struct buffer_head *bh;
*bhp = NULL;
if (offset >= journal->j_maxlen) {
printk(KERN_ERR "JBD: corrupted journal superblock\n");
return -EIO;
}
err = journal_bmap(journal, offset, &blocknr);
if (err) {
printk (KERN_ERR "JBD: bad block at offset %u\n",
offset);
return err;
}
bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
if (!bh)
return -ENOMEM;
if (!buffer_uptodate(bh)) {
/* If this is a brand new buffer, start readahead.
Otherwise, we assume we are already reading it. */
if (!buffer_req(bh))
do_readahead(journal, offset);
wait_on_buffer(bh);
}
if (!buffer_uptodate(bh)) {
printk (KERN_ERR "JBD: Failed to read block at offset %u\n",
offset);
brelse(bh);
return -EIO;
}
*bhp = bh;
return 0;
}
/*
* Count the number of in-use tags in a journal descriptor block.
*/
static int count_tags(struct buffer_head *bh, int size)
{
char * tagp;
journal_block_tag_t * tag;
int nr = 0;
tagp = &bh->b_data[sizeof(journal_header_t)];
while ((tagp - bh->b_data + sizeof(journal_block_tag_t)) <= size) {
tag = (journal_block_tag_t *) tagp;
nr++;
tagp += sizeof(journal_block_tag_t);
if (!(tag->t_flags & cpu_to_be32(JFS_FLAG_SAME_UUID)))
tagp += 16;
if (tag->t_flags & cpu_to_be32(JFS_FLAG_LAST_TAG))
break;
}
return nr;
}
/* Make sure we wrap around the log correctly! */
#define wrap(journal, var) \
do { \
if (var >= (journal)->j_last) \
var -= ((journal)->j_last - (journal)->j_first); \
} while (0)
/**
* journal_recover - recovers a on-disk journal
* @journal: the journal to recover
*
* The primary function for recovering the log contents when mounting a
* journaled device.
*
* Recovery is done in three passes. In the first pass, we look for the
* end of the log. In the second, we assemble the list of revoke
* blocks. In the third and final pass, we replay any un-revoked blocks
* in the log.
*/
int journal_recover(journal_t *journal)
{
int err;
journal_superblock_t * sb;
struct recovery_info info;
memset(&info, 0, sizeof(info));
sb = journal->j_superblock;
/*
* The journal superblock's s_start field (the current log head)
* is always zero if, and only if, the journal was cleanly
* unmounted.
*/
if (!sb->s_start) {
jbd_debug(1, "No recovery required, last transaction %d\n",
be32_to_cpu(sb->s_sequence));
journal->j_transaction_sequence = be32_to_cpu(sb->s_sequence) + 1;
return 0;
}
err = do_one_pass(journal, &info, PASS_SCAN);
if (!err)
err = do_one_pass(journal, &info, PASS_REVOKE);
if (!err)
err = do_one_pass(journal, &info, PASS_REPLAY);
jbd_debug(1, "JBD: recovery, exit status %d, "
"recovered transactions %u to %u\n",
err, info.start_transaction, info.end_transaction);
jbd_debug(1, "JBD: Replayed %d and revoked %d/%d blocks\n",
info.nr_replays, info.nr_revoke_hits, info.nr_revokes);
/* Restart the log at the next transaction ID, thus invalidating
* any existing commit records in the log. */
journal->j_transaction_sequence = ++info.end_transaction;
journal_clear_revoke(journal);
sync_blockdev(journal->j_fs_dev);
return err;
}
/**
* journal_skip_recovery - Start journal and wipe exiting records
* @journal: journal to startup
*
* Locate any valid recovery information from the journal and set up the
* journal structures in memory to ignore it (presumably because the
* caller has evidence that it is out of date).
* This function does'nt appear to be exorted..
*
* We perform one pass over the journal to allow us to tell the user how
* much recovery information is being erased, and to let us initialise
* the journal transaction sequence numbers to the next unused ID.
*/
int journal_skip_recovery(journal_t *journal)
{
int err;
journal_superblock_t * sb;
struct recovery_info info;
memset (&info, 0, sizeof(info));
sb = journal->j_superblock;
err = do_one_pass(journal, &info, PASS_SCAN);
if (err) {
printk(KERN_ERR "JBD: error %d scanning journal\n", err);
++journal->j_transaction_sequence;
} else {
#ifdef CONFIG_JBD_DEBUG
int dropped = info.end_transaction - be32_to_cpu(sb->s_sequence);
#endif
jbd_debug(1,
"JBD: ignoring %d transaction%s from the journal.\n",
dropped, (dropped == 1) ? "" : "s");
journal->j_transaction_sequence = ++info.end_transaction;
}
journal->j_tail = 0;
return err;
}
static int do_one_pass(journal_t *journal,
struct recovery_info *info, enum passtype pass)
{
unsigned int first_commit_ID, next_commit_ID;
unsigned long next_log_block;
int err, success = 0;
journal_superblock_t * sb;
journal_header_t * tmp;
struct buffer_head * bh;
unsigned int sequence;
int blocktype;
/* Precompute the maximum metadata descriptors in a descriptor block */
int MAX_BLOCKS_PER_DESC;
MAX_BLOCKS_PER_DESC = ((journal->j_blocksize-sizeof(journal_header_t))
/ sizeof(journal_block_tag_t));
/*
* First thing is to establish what we expect to find in the log
* (in terms of transaction IDs), and where (in terms of log
* block offsets): query the superblock.
*/
sb = journal->j_superblock;
next_commit_ID = be32_to_cpu(sb->s_sequence);
next_log_block = be32_to_cpu(sb->s_start);
first_commit_ID = next_commit_ID;
if (pass == PASS_SCAN)
info->start_transaction = first_commit_ID;
jbd_debug(1, "Starting recovery pass %d\n", pass);
/*
* Now we walk through the log, transaction by transaction,
* making sure that each transaction has a commit block in the
* expected place. Each complete transaction gets replayed back
* into the main filesystem.
*/
while (1) {
int flags;
char * tagp;
journal_block_tag_t * tag;
struct buffer_head * obh;
struct buffer_head * nbh;
cond_resched(); /* We're under lock_kernel() */
/* If we already know where to stop the log traversal,
* check right now that we haven't gone past the end of
* the log. */
if (pass != PASS_SCAN)
if (tid_geq(next_commit_ID, info->end_transaction))
break;
jbd_debug(2, "Scanning for sequence ID %u at %lu/%lu\n",
next_commit_ID, next_log_block, journal->j_last);
/* Skip over each chunk of the transaction looking
* either the next descriptor block or the final commit
* record. */
jbd_debug(3, "JBD: checking block %ld\n", next_log_block);
err = jread(&bh, journal, next_log_block);
if (err)
goto failed;
next_log_block++;
wrap(journal, next_log_block);
/* What kind of buffer is it?
*
* If it is a descriptor block, check that it has the
* expected sequence number. Otherwise, we're all done
* here. */
tmp = (journal_header_t *)bh->b_data;
if (tmp->h_magic != cpu_to_be32(JFS_MAGIC_NUMBER)) {
brelse(bh);
break;
}
blocktype = be32_to_cpu(tmp->h_blocktype);
sequence = be32_to_cpu(tmp->h_sequence);
jbd_debug(3, "Found magic %d, sequence %d\n",
blocktype, sequence);
if (sequence != next_commit_ID) {
brelse(bh);
break;
}
/* OK, we have a valid descriptor block which matches
* all of the sequence number checks. What are we going
* to do with it? That depends on the pass... */
switch(blocktype) {
case JFS_DESCRIPTOR_BLOCK:
/* If it is a valid descriptor block, replay it
* in pass REPLAY; otherwise, just skip over the
* blocks it describes. */
if (pass != PASS_REPLAY) {
next_log_block +=
count_tags(bh, journal->j_blocksize);
wrap(journal, next_log_block);
brelse(bh);
continue;
}
/* A descriptor block: we can now write all of
* the data blocks. Yay, useful work is finally
* getting done here! */
tagp = &bh->b_data[sizeof(journal_header_t)];
while ((tagp - bh->b_data +sizeof(journal_block_tag_t))
<= journal->j_blocksize) {
unsigned long io_block;
tag = (journal_block_tag_t *) tagp;
flags = be32_to_cpu(tag->t_flags);
io_block = next_log_block++;
wrap(journal, next_log_block);
err = jread(&obh, journal, io_block);
if (err) {
/* Recover what we can, but
* report failure at the end. */
success = err;
printk (KERN_ERR
"JBD: IO error %d recovering "
"block %ld in log\n",
err, io_block);
} else {
unsigned long blocknr;
J_ASSERT(obh != NULL);
blocknr = be32_to_cpu(tag->t_blocknr);
/* If the block has been
* revoked, then we're all done
* here. */
if (journal_test_revoke
(journal, blocknr,
next_commit_ID)) {
brelse(obh);
++info->nr_revoke_hits;
goto skip_write;
}
/* Find a buffer for the new
* data being restored */
nbh = __getblk(journal->j_fs_dev,
blocknr,
journal->j_blocksize);
if (nbh == NULL) {
printk(KERN_ERR
"JBD: Out of memory "
"during recovery.\n");
err = -ENOMEM;
brelse(bh);
brelse(obh);
goto failed;
}
lock_buffer(nbh);
memcpy(nbh->b_data, obh->b_data,
journal->j_blocksize);
if (flags & JFS_FLAG_ESCAPE) {
*((__be32 *)bh->b_data) =
cpu_to_be32(JFS_MAGIC_NUMBER);
}
BUFFER_TRACE(nbh, "marking dirty");
set_buffer_uptodate(nbh);
mark_buffer_dirty(nbh);
BUFFER_TRACE(nbh, "marking uptodate");
++info->nr_replays;
/* ll_rw_block(WRITE, 1, &nbh); */
unlock_buffer(nbh);
brelse(obh);
brelse(nbh);
}
skip_write:
tagp += sizeof(journal_block_tag_t);
if (!(flags & JFS_FLAG_SAME_UUID))
tagp += 16;
if (flags & JFS_FLAG_LAST_TAG)
break;
}
brelse(bh);
continue;
case JFS_COMMIT_BLOCK:
/* Found an expected commit block: not much to
* do other than move on to the next sequence
* number. */
brelse(bh);
next_commit_ID++;
continue;
case JFS_REVOKE_BLOCK:
/* If we aren't in the REVOKE pass, then we can
* just skip over this block. */
if (pass != PASS_REVOKE) {
brelse(bh);
continue;
}
err = scan_revoke_records(journal, bh,
next_commit_ID, info);
brelse(bh);
if (err)
goto failed;
continue;
default:
jbd_debug(3, "Unrecognised magic %d, end of scan.\n",
blocktype);
brelse(bh);
goto done;
}
}
done:
/*
* We broke out of the log scan loop: either we came to the
* known end of the log or we found an unexpected block in the
* log. If the latter happened, then we know that the "current"
* transaction marks the end of the valid log.
*/
if (pass == PASS_SCAN)
info->end_transaction = next_commit_ID;
else {
/* It's really bad news if different passes end up at
* different places (but possible due to IO errors). */
if (info->end_transaction != next_commit_ID) {
printk (KERN_ERR "JBD: recovery pass %d ended at "
"transaction %u, expected %u\n",
pass, next_commit_ID, info->end_transaction);
if (!success)
success = -EIO;
}
}
return success;
failed:
return err;
}
/* Scan a revoke record, marking all blocks mentioned as revoked. */
static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
tid_t sequence, struct recovery_info *info)
{
journal_revoke_header_t *header;
int offset, max;
header = (journal_revoke_header_t *) bh->b_data;
offset = sizeof(journal_revoke_header_t);
max = be32_to_cpu(header->r_count);
while (offset < max) {
unsigned long blocknr;
int err;
blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset)));
offset += 4;
err = journal_set_revoke(journal, blocknr, sequence);
if (err)
return err;
++info->nr_revokes;
}
return 0;
}